Although I Am Not Bed Ridden, I Think I Have

Although I am not bed ridden, I think I have a bed sore on my butt. I went to prompt care and the nurse practitioner said it was herpes. She consulted with the physician on staff who seemed to disagree but all they did was a culture and give me herpes medicine. Could I have a bed sore if I was in a car for over 12 hours and irritated?